Apparatus for the manufacture of lamps and the like



June 20, 1939. NQVQTNY 2,163,177

APPARATUS FOR THE MANUFACTURE OF LAMPS AND THE LIKE Filed Feb. 16, 1935 2 Sheets-Sheet l IT 11"] "L F illlll II I60 i o C74 90 I28 \08 EN" MI I62 INVEIVVTOR EME ENOVOTJVY BY %4MVF?QM ATTORNEYS 20, 1939. NQVOTNY 2,163,177

APPARATUS FOR THE MANUFACTURE OF L AMPS AND THE LIKE Filed Feb. 16, 1935 2 Sheets-Sheet '2 T3112. 3 &

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- INVENTOR.

EMIL E. NOVOIA Y ATTORNEYS Patented June 20, 1939 2,163,177 arrsaa'ros roa THE monomer: or rams AND 'rnr. mm

Emil E. Novotny, Philadelphia, Pa., assignor, by mesne assignments, to Durite Plastics, Incorporated, Philadelphia, Pa., a corporation of Pennsylvania Application February 1c, 1935, Serial No. 6,778

12 Claims.

This invention relates to the manufacture of composite articles having a fragile part and a molded plastic part, and more particularly to electrical devices such as lamps, radio tubes, heater tubes, photo-electric cells, and the like, which comprise a sealed glass envelope combined with a base.

Inaccordance with'prior practice the base, whether made .of metal. as in an ordinary lamp, on of insulation as in the case of a radio tube, is made separately and subsequently cemented to theeiivelope, after which the lead wires from the envelope must be soldered to appropriate contacts on the base. It is extremely. diflioult to satisfactorily cement the glass envelope to the bate. Iii the case of an ordinary lamp the metallic base must be made in two parts mutually insulated from one another and to which the lead wires must be separately soldered.

The object of my invention is to generally improve the manufacture of composite articles and electrical devices, andmore specifically is to form a base directly on a glass envelope by molding the base around part of the envelope. In this manner the parts are permanently secured together and in all practical respects are combined to form an integral structure.

In. accordance with a further feature and object of my invention, the base is preferably molded by transfer or extrusion, the molding material being preliminarily placed in a pressure chamber and subjected to heat and pressure in order to plasticize the same and to extrude the same in a relatively thin free-flowing stream into the mold for the base. A part of the glass envelope is itself caused to act as one wall of the mold cavity, and this is made possible without breakage of the glass envelope largely because the molding material does not enter the mold until it'is in a free-flowing condition.

Another, object of my invention is to further guard against the possibility of breakage or injury tothe-glass envelope, even when using a molding material such as synthetic resins of the permanently infusibly thermosetting type (Durltel, "Bakelite, "Durez, etc.), which materials molding pressure exceeds the permissible or desired pressure.

The glass envelope ordinarily includes a reentrant tube or stem through which lead wires pass. One object of my invention is to prevent the molding material from filling the reentrant tube.

Another object of my invention is to facilitate the provision of suitable connections or terminals for contact with a conventional socket.

To the accomplishment of the foregoing and other objects which will hereinafter appear, my invention consists in the improved method and apparatus elements and their relation one to.

the other as hereinafter are more particularly described in the specification and sought to be defined in the claims. The specification is accompanied by drawings, in which:

Fig. 1 is a partially sectioned elevation of a press equipped with apparatus for practicing my invention;

Fig. 2 is an enlarged section taken through the pressure chamber and mold;

Fig. 3 is an enlarged section through the mold;

Fig. 4 is a detail of a washer or stopper for blocking the open end of the reentrant tube;

Fig. 5 is a perspective view of the mold in open condition;

Fig. 6 is a partially sectioned elevation through apparatus including multiple pressure chambers feeding multiple mold cavities; and

Fig. 7 is a side elevation of a completed lamp bulb made in accordance with my invention.

The present application is a continuation in,

part of my earlier copending application Ser. No. 340,605 filed Feb. 16, 1929, now Patent 1,993,942, in which I disclose molding apparatus including a pressure chamber for heating and plasticizing and thereby transferring synthetic resinous material in a free-flowing condition into a communicating mold. I there explained that the pressure can thus be reduced to so low a point that it is possible to mold the material in mold cavities defined in glass, and this makes possible the molding of lamp bases and radio tube bases directly onto the glass tube enclosing the operating elements; and, further, that this dispenses with the operation of first forming a, separate base and subsequently cementing such base to the glass bulb, which is altogether an undesirable process in that a wholly satisfactory job of cementing cannot be done. I

The present application is also a continuation in part of my prior copending application Ser. No. 423,160 filed Jan. 24, '1930 now Patent 1,997,074, in which I disclose a transfer press somewhat'as above but modiileclto provide a pressure diilerentialrbetween the pressure chamber and the mold so that a smalldiameter pressure chamber may be used, if desired, for the extrusion of molding material un:

der super-hydraulic pressure, while at the same a time the molding pressure may be limited to be and cooperating with a plunger P stationariiy mounted on the fixed upper head ll of the press. The pressure chamber and plunger cooperate to extrude molding material into a two-part mold M which, in accordance with the present invention, has an open side closed by the glass envelope E of an electrical device, in this case a lamp. The entire press is operated by upward move- .ment of a main ram R, which moves-the mold M against pressure chamber C, and then moves the pressure chamber against plunger P. The upward movement of pressure chamber C is preferably yieldably resisted by auxiliary rams A, thus limiting the force with whichmold M is held closed.

The molding material forced from the pressure chamber into the mold is molded into a lamp base formed directly around the end of the glass envelope, resulting in a lamp of the general type illustrated in Fig. 7 and comprising a glass envelope E having molded directly on the stem end I2 thereof a base i made wholly of a moldable insulation material, preferably a synthetic resin. Two lead wires extend from the lamp filament through the lamp stem and through insulation base it. One of these wires is connected to a terminal It at the bottom of the base, while the other wire is connected to a terminal ll formed at one side of the base. Terminal II is preferably located at the upper surface of one of the threads 20 on the base, thereby insuring flrm contact against the terminal when the lamp is screwed into a socket.

The mode of formation of the lamp may be described in greater detail with reference to Figs.-

2 through 5 of the drawings, and referring to these figures the mold M is a two-part separable mold comprising a lower part 22 and an upper part 24 between which is defined a mold cavity 28 (Fig. 5) conforming to the-configuration of lamp base I 4. Part 24 is provided with passages 20 and 30 (Fig. 5) dimensioned to receive the lead wires 32 and 34 of lamp filament ll. The outer walls of the mold are preferably recessed at the ends of passages 20 and 30, as is indicated at 38 and II, thereby providing room for any excess length of lead wire (see Fig. 3).

To prevent the molding material from entering reentrant tube 42 of the envelope, I stop the end of the reentrant tube with a suitable insulation washer 44, best shown in Fig. 4. The washer is provided with small holes I dimensioned to receive the lead'wires, and a larger hole ll dimensioned to receive the evacuation tube or pump stem 50. The holes 4 and I. are dimensioned to fit snugly, and the washer M is held in place until molding material enters the mold cavity, at which time the washer is pressed firmly against the end of the envelope and under pres- .of theenvelope.

sure is compressed more tightly around the terminal wires and stem, thus effectively stopping any flow of molding material into reentrant tube 42 of the lamp. The presence of molding material in the reentrant tube might be thought by some to be objectionable in appearance or in operation or for wastage of material. I have found that certain grades of phenolic laminated sheet material possess the punchability, resilience, strength, electrical insulating properties, and resistance to elevated temperature nwded for a washer of this type, but it will be'understood that other materials may be used.

In operation, the lamp envelope E is preliminarily provided with washer M which is slipped into place over lead wires I! and N. The envelope is then applied to the open side of the mold, lead 82 being guided through passage 2., and lead 34 being guided through passage 30. If excessively long, the ends of leads I! and II are bent over, but the leads are not pulled with unnecessary tightness. The mold and lamp assembly is thereupon placed in. the press by setting the same in heated angle plate 52, and the lamp envelope is held in place by a pressure foot I (Fig. 2) yieldably urged against the outer end In the present case the pressure foot is urged inwardly by a compression spring 56 housed in a cylinder 58 and bearing against the inner end of a plunger ll reciprocable in cylinder Bl. The pressure foot may be retracted during the loading or unloading of the lamp and mold by means of a manually operable handle 82 having a camming end 84 pivoted on a block 66 carried on a rod 68 connected to plunger ll, Block 6 is adJustably held on rod II by locked nuts II. The pressure of spring 58 is preferably adjustable in order to control the relief pressurelimit for the molding operation, and in the present case this adjustment is obtained by the use of a suitable number of loading washers 122 When the mold and lamp assembly is placed on angle plate 52, handle I is moved downwardly from horizontal to vertical position, thereby 'releasing pressure foot, ll to bear against glass envelope E.

A charge of molding material is placed in pressure chamber C and is heated by a heating medium passing through conduits ll. Plunger P may itself be heated by mounting the same on a heated platen It, in which'case a layer of heat insulating material II is preferably interposed between platen II and press head ll. It will be understood that upon relative movement of plunger P and pressure chamber 0, the molding material is plasticized and extruded through a refatively tiny discharge opening I! at the bottom of the pressure chamber. The lower end of plunger P and pressure chamber 0 are preferably matingly tapered, as is indicated at N, and the wall of the plunger may be grooved as at to form a sealing ring which fills with molding material and thereby seals the plunger against leakage even at very high pressure, although for the present purpose it is not necessary to use superhydraulic pressures.

The material extruded through outlet 82 flows directly into a feeder channel ll preferably formed between the parts I! and 24 of the mold, as is best shown in Fig. 5. Feeder channel ll registers with outlet 82, this registration being insured by dowels OI mating with dowel holes if at the top of the mold. Channel ll preferably diverges, as shown in Fig. 5, thereby affording free rapid transfer of the molding material from the pressure chamber into the mold, and at the same tu're, I believe it preferable to locate the] same time facilitating removal of themolding material from the feeder channel as well as the mold cavity upon completion of the molding operation. Thl'scomplete removaland emptying of the mold and passages leading thereto is essential when dealing with a permanently setting resin.

Referring-to Figs.'3 and 5, it'will be noted that feeder channel 88 opens into an annular space shaped to form a small circular flange 94 (Fig. 3) forming a cup-like recess 96 at the bottom 'of the lamp base. This recess facilitates a subsequent drop-soldering operation for the center lamp terminal I5 shown in Fig. 7. The feeder channel or gate 88 is preferably located at the outer end of projecting lip 94, as shown, because this facilitates subsequent removal of the gate and grinding of any surplus material at the junction point.

The molding material enters the mold cavity in a plastic free-flowing condition and spreads around the lead wires, against the stop washer 44, around the end II'III of glass envelope E, and accurately fills out the thread grooves 98. The end I00 is preferably ridged as indicated at I02, or otherwise shaped to form undercut portions, so that the envelope and base are inseparabiy locked together. When the pressure in the mold builds up to a value greater than the permissible value determined by compression spring 55, the glass envelope moves outwardly with pressure foot 54, and the excess molding material is freely discharged around the periphery I04 of the mold cavity. The charge of molding material initially placed in the pressure chamber is preferably only slightly greater than needed to form the base, and when the excess flows from the mold, the glass envelope is instantly restored to initial position, thereby cutting off the excess material at mold periphery I04. The material is severed sharply, and the base isgiven a well-defined cleanly molded lip requiring little if any trimming or finishing.

The permissible outward movement of the glass envelope is preferably limited to a relatively slight amount by stop means, here exemplified by an ear I06 on pressure foot 54 cooperating with an adjustable stop screw I08 the adjustment of which is locked by nut IIII. This limitation of outward 'movement is desirable in order to prevent stress ly necessary to elevate the pressure chamber from the mold; retract pressure foot 54 by means of handle 62; thereupon remove the lamp and mold from angle plate 52, with the assistance, if desired, of an ejector rod IIZ; open the mold by separating part 24 from part 22; and extract the lamp, with its molded base and projecting lead wires, from the mold. It was previously mentioned that a recess 96 is formed in the base around lead wire 32, and it may now be re marked that a recess II4 is similarly formed around lead wire 34. The present base is a threaded base intended for use in a conventional threaded lamp socket, and lead wire 34 is used for contact with the threaded part of the socket. Tocomplete the lamp, the ends of leads 32 and 34 may be clipped off at recesses 96 and H4, and metallic contact'terminals may be formed by simply droppingmolten solder in recesses 96 and I I4. Because of surface tension, the molten metal takes the convex projecting form indicated at I8 and Win Fig; 7. While the location of terminal I8 may be varied with respect to the thread strucat the upper partof a thread,'as"sh'own,so "that.

the upward pressuref'caused when the'lamp' has been screwed into a'socket elevates terminal I8 against the immediately superjacent socket thread.

Because it is desirable to limit the outward or venting -movement of the glass envelope to, a

slight amount, I prefer to further safeguard the glass envelope against breakage, as in the event of an excessive charge of molding material being placed in the pressure chamber, by affording additional pressurerelief by separation at the parting face of the mold. This result is best accom-' plished by using a press arrangement such as I have illustrated in Fig. 1, and referring to that figure it will be seen that the press comprises a stationary bed I20, and a stationary upper head mounted above bed I 20 on four posts or strain rods I22. A lower head I24, vertically reciprocable on strain rods I22, is carried by a main operating ram R. the hydraulic cylinder for which is not shown in the drawings. A support plate I26 is mounted on head I24 and carries angle plate 52 as well as the assembly for pressure-foot 54 and ejector rod II2 (the operating mechanism for which is not shown).

Pressure chamber C is mounted on a vertically I reciprocable platen I28 guided by strain rods I22 and carried by piston rods I30 located between the front and rear strain rods and connected to auxiliary or opposed hydraulic cylinders A which are mounted on stationary head 80. Platen I28 is constantly but yieldably urged downwardly by hydraulic mechanism A, and the downward movement of the platen when the press is opened is limited by stop collars I32. In the drawings, the press is shown in open condition but platen I28 is elevated above stop collars I32'in order to more clearly show the manner in which the platen is mounted on piston rods I30.

When the press is open, the bottom head I24 is in lowermost position, and the lamp and mold are readily placed between angle plate 52 and pressure foot 56. The platen I28 is in intermediate position and is dropped well below plunger P,

thus facilitating the deposit of a measured charge of molding material in the pressure chamber.

The press is closed by elevating main ram R,

thereby bringing the mold against the bottom of the pressure chamber and forming a continuous flow passage from the pressure chamber into the mold. At the same time stop mechanism I06, I08 becomes efiective. The mold is held closed by a force dependent on the area of and pressure applied to the pistons in auxiliary cylinders A.

Main operating ram R continues its upward movement, thereby carrying the mold and pressure chamber assembly upwardly against plunger P, which, of course, ejects the charge of molding material from the pressure chamber into the mold. Injury to the lower ends of the plunger and pressure chamber may-be prevented by the use of appropriate stop blocks I34.

It should be appreciated that mold M is held closed yieldably rather than fixedly, and whenever ithe pressure in the mold cavity exceeds a predetermined desired or permissible value, the halves of the mold may separate, thus affording prompt pressure relief at the parting face of the mold. Reverting to Fig. 5, it will be seen that I provide overflow channels I36 following or contouring the outline of the mold cavity. I further provide an overflow channel I38 at the upper face of the mold immediately adjacent feeder channel 48. When the mold pressure is relieved by momentary opening or chattering of the mold assembly, the separation may take place at the parting face of the mold or the parting face between the mold and the pressure chamber, or both, and excess material is correspondingly discharged into the overflow channels I or In or both.

If desired, the relief pressure determined by pressure foot 54 may be given a different value than that determined by auxiliary cylinders A, preferably a lower value so that ordinarily the pressure relief takes place around the glass envelope alone. With such an arrangement, the

additional pressure relief made possible is in-' tended to become operative only when the pressure is incapable of being relieved sufliciently fast around the envelope.

Upon completion of the molding operation, ram R is lowered, thereby first separating the pressure chamber from the plunger, and thereafter separating the mold from the pressure chamber. Pressure foot 54 is retracted and the mold and lamp'removed from the press. The mold is a portable or hand mold, and a plurality of such molds are provided. One may be loaded with a lamp envelope to be provided with a base, while another may be in the press undergoing the molding operation, and a third may have been removed from the base and be having the lamp with its freshly molded base removed from the mold. This, of course, speeds up the molding operation.

To further this end, a number of mold cavities may be fed from a single pressure chamber, or a series of mold cavities may be fedfrom a plurality of pressure chambers. An arrangement of this kind is illustratedin Fig. 6 in which I show the mold as comprising separable upper and lower parts I40 and I42 defining a plurality of mold cavities I44, each open at one end, just as has heretofore been described. Molding materialis fed to the mold cavities from a plurality of pressure chambers I46 mounted in a common heated bed plate I48. The pressure chambers cooperate with mating plungers I50. The mold and pressure chambers are aligned by suitable pins I52, while the upper and lower mold parts are aligned by Pins I54. The molding material is fed into a common lateral feeder channel I56 recessed in the top face of the upper mold portion I40 and underlying and directly connected with the outlets I58 of the pressure chambers. The mold cavities have individual and preferably diverging feeder channels IBU which connect with lateral feeder channel I56. It will be understood that the arrangement is generally like that heretofore described except that the mold is' elongated in a direction transverse to the drawings when looking at Figs. 1, 2, and 3. The mold is accordingly similarly placed on a heated angle plate attached to the lower head of the press, and several molds may similarly be made interchangeable with one another, thus permitting the use of one in the press during the molding operation while another is being separated from or assembled with the lamp envelopes. During the molding operation, the several lamps are held in position in the mold by a multiplicity of pressure feet like that heretofore described. While I show one pressure chamber for each two and a half mold cavities, it will be understood that 1 am not limited to this specific construction, but may make such arrangement of pressure chambers and mold cavities with interconnecting feeder channels as may suit my purpose.

It is believed that the method of my invention, as well as the construction and operation of the apparatus for practicing the same. and the many advantages thereof, will be apparent from the foregoing detailed description. The lamp base is essentially a single-piece insulation base molded directly around the glass envelope and permanently secured thereto. While not essential,

even so high-grade an insulating material as the Y permanently infusibly. thermosetting synthetic resins may be used. The material is molded directly around the glass envelope without injury or breakage of the glass envelope. Electrical terminals for connection to the lead wires are obtained in convenient manner. The lamp base has molded thereon any necessary means for cooperating with a conventional socket, the most common example, of course, being the use of threads, but inserted bayonet pins or bottom prongs, or the like may also be molded in place for use with special sockets.

It will be apparent that while I have shown and described my invention in preferred form, many changes and modifications may be made without departing from the spirit of the invention, defined in the following claims.

I claim:

1. Apparatus for molding a plastic composition base directly around the lower end of a sealed fragile glass envelope, said apparatus comprising a mold defining a mold cavity for producing a base, said mold being open at one side corresponding to the top of the baseand being dimensioned to receive the lower end of the glass envelope, means to hold the glass envelope in the opening of the mold, passages in said mold for receiving the ends of lead wires projecting from the glass envelope, a pressure chamber in flow communication with said mold, means to heat the pressure chamber, and a plunger movable in said chamber for extruding molding materialtherefrom into said mold, and means to prevent the pressure in the mold from exceeding a low pressureincapable of breaking the envelope, regardless of the pressure reached in the pressure chamber.

2. Apparatus for molding a plastic composition base directly around the lower end of a sealed glass envelope, said apparatus comprising a mold defining a mold cavity for producing a base, said mold being open at one side corresponding to the top of the base and being dimensioned to receive the lower end of the glass envelope, yieldable means to hold the glass envelope in the opening of the mold, passages in said mold for receiving the ends of lead wires projecting from the glass envelope, protuberances in the mold cavity at the lead wire passages to form drop solder recesses on the base, stop means to limit the movement of the yieldable means, a pressure chamber in flow communication with said mold, a plunger movable in said chamber for extruding molding material therefrom into said mold, and means to prevent the pressure in the mold from exceeding a. low pressure incapable of breaking the envelope regardless of the pressure reached in the pressure chamber. 7

3. Apparatus for molding a base directly on a sealed glass envelope, said apparatus comprising a mold defining a mold cavity for producing a base, said mold being open at one side corresponding to the top of the base and being dimensioned to receive the lower end of the glass envelope,

area"? yieldable means to hold the glass envelope in the opening of the mold, passages in said mold for receiving the ends of lead wires projecting from the glass envelope, a pressure chamber in flow communication "with said mold, a plunger movable in said chamber for extruding molding material therefrom into said mold, and means to heat the pressure chamber.

4. Apparatus for molding a base directly on a sealed glass envelope, said apparatus comprising a two-part mold defining a mold cavity for producing a base, said mold being open at one side corresponding to the top of the base and being dimensioned to receive the lower end of the glass envelope, means to hold the glass envelope in the opening of the mold, passages in said mold for receiving the ends of lead wires projecting from the glass envelope, a pressure chamber in flow communication with said mold, a plunger movable in said chamber for extruding molding material therefrom into said mold, means for causing relative movement of the plunger and the pressure chamber, and yieldable means forholding the mold closed during the molding operation, said means being so adjusted as to afford opening and discharge of excess material from the mold at a relatively low pressure insufilcient to injure the glass envelope.

5. Apparatus for molding a base directly on a sealed glass envelope, said apparatus comprising a two-part mold defining a mold cavity for producing a base, said mold being open at one side corresponding to the top of the base and being dimensioned to receive the lower end of the glass envelope, yieldable means to hold the glass envelope in the opening of the mold, passages in said mold for receiving the ends of lead wires projecting from the glass envelope, a pressure chamber in flow communication with said mold, a plunger movable in said chamber for extruding molding material therefrom into said mold, means r causing relative movement of the plunger nd pressure chamber, and yieldable means for holding the mold closed' 'during the molding operation, the parts being so adjusted that the yieldable means holding the envelope in the mold and the yieldable means holding the mold closed afford opening and discharge of excess material from the mold at a relatively low pressure insuflicient to injure the glass envelope.

' 6. Apparatus for molding a base directly on a sealed glass envelope, said apparatus comprising a two-part mold defining a mold cavity for producing a threaded base, said mold being open at one side corresponding to the top of the base and being dimensioned to receive the lower end of the glass envelope, yieldable means to hold the glass envelope in the opening of the mold, pas

sages in said mold for receiving the ends of lead wires projecting from the glass envelope, stop means to limit the movement of said means, passages in said mold for receiving the ends of lead wires projecting from the glass envelope, a small diameter pressure chamber in flow communication with said mold, a plunger movable in said chamber for extruding molding material therefrom into said mold, means to heat the pressure chamber, a press including a main operating ram for causing relative movement of the plunger and pressure chamber, and auxiliary rams for yieldably holding the mold closed during the molding operation, the parts being so adjusted that the yieldable means holding the envelope in the mold and the yieldable means holding the mold closed afiord opening and discharge of excess material from the mold at a relatively low pressure insumcient to injure the glass envelope.

7. Apparatus for the manufacture of a composite article having a fragile preliminarily manufactured part and a part made of a moldable plastic, said apparatus comprising amold defining a mold cavity for producing the plastic part of the article, said mold being open at one side corresponding to the point of connection between the fragile and plastic parts of the\ article, said opening being dimensioned to receive and to be closed by the fragile part of the article, means to hold the fragile part in the aforesaid mold opening, a pressure chamber in flow communication with said mold, means to heat the pressure chamber, a plunger movable in said chamber for extruding the molding material from the chamber into the mold, and means to prevent the pressure in the mold from reaching a pressure capable of breaking the fragile part of the article, regardless of the pressure in the pressure chamber.

8. Apparatusfor the manufacture of a composite article having a fragile preliminarily manufactured part and a part made of a moldable plastic, said apparatus comprising a mold defining a mold cavity for producing the plastic part of the article, said mold being open at one side corresponding to the point of connection between the fragile and plastic parts of the article, said opening being dimensioned to receive and to be closed by the fragile part of the article, yieldable means to hold the fragile part in the mold opening, a pressure chamber in flow communication with said mold, and a plunger movable in said chamber for extruding molding material therefrom into said mold.

9. Apparatus for the manufacture of a composite article having a fragile preliminarily manufactured part and a part made of a thermosetting plastic moldable under heat and pressure, said apparatus comprising amold defining a mold cavity for producing the plastic part of the article, said mold being open at one side corresponding to the point of connection between the fragile and plastic parts of the article, said opening being dimensioned to be received and to be closed by the fragile part of the article, yieldable means to hold the fragile part of the mold opening, whereby the fragile part forms a part of the wall of the mold cavity, stop means to limit the movement of the yieldable means, a pressure chamber in flow communication with said mold, a plunger movable in said chamber for extruding molding plastic part of the article, said mold being open at one side corresponding to the point of connection between the fragile and plastic parts of the article, said opening being dimensioned to receive and to be closed by the fragile part of the article, means to hold the fragile part in the mold opening, a pressure chamber in flow communication with said mold, a plunger movable in said chamber for extruding molding material therefrom into said mold, means for causing relative movement of the plunger and pressure chamber, yieldablemeans for holding the mold closed during the molding operation, said means being so adjusted as to afford opening and-discharge of excess material from the mold at a relatively low pressure insuflicient to injure the fragile part.

11. Apparatus for the manufacture of a composite article having a fragile preliminarily manufactured part and a part made of a moldable plastic, saidapparatus comprising a two-part mold defining a mold cavity for producing the plastic part of the article, said mold being open at one side corresponding to the point of connection between the fragile and plastic parts of the article, said opening being dimensioned to receive and to be closed by the fragile part of the article, yieldable means to hold the fragile part in the mold opening, a presure chamber in flow communication with said mold, a plunger movable in said chamber for extruding molding material therefrom into said mold, means for causing relative movement of the plunger and pressure chamber, and yieldable means for holding the mold closed during the molding operation, the parts being so adJusted that the yieldable means holding the fragile part in the mold and the yieldable means holding the mold closed aflord opening and discharge of excess material from the mold at a relatively low pressure insufllcient to injure the fragile part. 1

12. Apparatus for the manufacture of a composite article having a fragile preliminarily manufactured part and a part made of a mob-ole plastic, said apparatus comprising a two-part mold defining a mold cavity for producing the plastic part of the article, said mold being open at one sidecorrespondlng tothepoint oi connection between the fragileand plastic parts offthe articlasaid opening being dimensioned to receive and to be closed-by thefrag'ile part of thearticle, x and yieldable means to hold the fragile part in the mold opening, stop meansto limit the movee ment of said yieldable means, a pressure chamber in flow communication with said mold, means to heat the pressure chamber, a plunger movable in said chamber for extruding molding material therefrom into said mold, means to heat the pressure chamber, a press including a main operating ram for causing relative movement of the plunger and pressure chamber, and auxiliary rams for yieldably holding the mold closed during the molding operation, the parts being so adjusted that the yieldable means holding the fragile part in the mold and the yieldable means holding the mold closed aiford opening and discharge of excess material from the mold at a relatively low pressure insumcient to inJure the fragile part.

EMIL E. NOVOTNY. 

